Read, calculate, print

Many programs have the same three parts, whatever they're about:

1. Read the input into variables.
2. Calculate the result from them.
3. Print the result.

Here the input is a temperature in Celsius, and the result is the same temperature in Fahrenheit:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        // 1. Read
        int celsius = Integer.valueOf(scanner.nextLine());
        // 2. Calculate
        double fahrenheit = celsius * 9 / 5.0 + 32;
        // 3. Print
        System.out.println(celsius + " C is " + fahrenheit + " F");
    }
}

25

25 C is 77.0 F

When a new problem looks hard, start by naming the three parts: what does the program get, what does it work out, and what does it show? Each part is often just a line or two.

Keeping the calculation in its own variable (fahrenheit) makes the print line short and gives the result a name.